Judge who holds swing vote on US Supreme Court to retire

Supreme Court Justice Anthony Kennedy announced his retirement on Wednesday, giving President Donald Trump a golden chance to cement conservative control of America’s top court.

Kennedy, 81, said in a statement he was stepping down after more than 30 years on the court. A Republican appointee, he has held the key vote on such high-profile issues as abortion, affirmative action, gay rights, guns, campaign finance and voting rights.

Kennedy said he had informed his colleagues and Trump of his plans, and that his retirement would take effect at the end of July.

Trump praised Kennedy as a man of "tremendous vision" and said his search for a new justice would begin "immediately".

Without Kennedy, the court will be split between four liberal justices who were appointed by Democratic presidents and four conservatives who were named by Republicans. Trump's nominee is likely to give the conservatives a solid majority and will face a Senate process in which Republicans hold the slimmest majority, but Democrats can't delay confirmation.

Trump already has a list of 25 candidates — 24 judges and Utah Senator Mike Lee — and has said he would choose a nominee from that list.

Abortion is likely to be one of the flash points in the nomination fight. Kennedy has mainly supported abortion rights in his time on the court, and Trump has made clear he would try to choose justices who want to overturn the landmark abortion rights case of Roe v. Wade. Such a dramatic step may not be immediately likely, but a more conservative court might be more willing to sustain abortion restrictions.

Interest groups across the political spectrum are expected to mobilise to support and fight the nomination because it is so likely to push the court to the right.

Republicans currently hold a bare 51-49 majority in the Senate, although that includes the ailing Senator John McCain of Arizona. If Democrats stand united in opposition to Trump's choice, Senate Majority Leader Mitch McConnell of Kentucky can lose no more than one vote. If the Senate divides 50-50, Vice-President Mike Pence could break a tie to confirm the nominee.

Kennedy's departure will be a massive change for the high court, where he has been the crucial swing vote for more than a decade. He has sided with the liberal justices on gay rights and abortion rights, as well as some cases involving race, the death penalty and the rights of people detained without charges at the Guantanamo Bay naval base. He has written all the court's major gay-rights decisions, including the 2015 ruling that declared same-sex marriage is a constitutional right nationwide.

However, he also has been a key vote when conservatives have won major rulings on the outcome of the 2000 presidential election in favour of George W. Bush, gun rights, limiting regulation of campaign money and gutting a key provision of the landmark federal Voting Rights Act.